Ceramic igniters have found increased use in certain ignition applications such as gas fired furnaces, stoves and clothes dryers. See, generally, U.S. Pat. Nos. 3,875,477, 3,928,910, 3,974,106, 4,260,872, 4,634,837, 4,804,823, 4,912,305, 5,085,237, 5,191,508, 5,233,166, 5,378,956, 5,405,237, 5,543,180, 5,785,911, 5,786,565, 5,801,361, 5,820,789, 5,892,201, 6,028,292, and 6,078,028.
While ceramic igniter designs and performance have improved, problems still exist that can prevent optimal functioning. One persistant problem is pentration of moisture or other fluids into the igniter electrical lead or contact portion, i.e. where electrical contacts mate with the igniter element, typically via a lead frame.
Penetrating fluids can originate from a variety of sources, including moisture from the surrounding area and the ambient atmosphere as well as liquid fuels such as kerosone that the ceramic element ignites.
Cooking evironments are especially problematic. Ceramic igniters used in gas stove settings frequently come into contact with spilled or splashed fluids (e.g. liquids, steam, etc.) emanating from pots or other apparatus on the stove.
Protective housing elements, particularly used in combination with a potting cement material (often an epoxy-based sealant), have been employed to avoid such fluid penetration, but such housings have not consistently provided satisfactory results. If fluid penetrates the igniter's protective housing, and contacts the electric leads therewithin, the igniter can short circuit and fail. Fluid penetration also can accelerate oxidation of the protected lead portion, which can result in premature igniter failure.
It thus would be desirable to have new ceramic igniters that could provide enhanced performance properties. It would be particularly desirable to have new ceramic igniters that have enhanced resistance to undesired fluid penetration and/or oxidation of the igniter's electrical contact portion.